The present invention relates to a binocular endoscope or similar instrument finding utility in the examination and in the surgical treatment of the interior of a hollow organ, as, for example, the urethra and the bladder. More particularly, the invention is directed to an endoscope provided with a pair of coextensive optical systems for directing light through two parallel equivalent optical paths, thus providing depth perception in the image of an object or field viewed.
Binocular or stereoscopic endoscopes are known in the prior art. For example, stereoscopic endoscopes utilizing flexible fiber optical systems have been described, such a system being the subject of Tasaki et al U.S. Pat. No. 3,520,587. Also, various optical systems have been utilized for obtaining an upright image, one such technique resorting to the twisting of fibers through 180.degree. and a second technique utilizing Porro prisms. In still other arrangements the optical fiber bundles or sheaths have been arranged to cross each other at their midpoints. However, the latter system results in an image inversion between raised and recessed portions. Focusing has been achieved through the use of auxiliary elements such as Amici prisms and the like.
In spite of extensive research and developmental work carried out in the general field of endoscopic devices, no completely satisfactory binocular device of this type has heretofore been produced, all of the prior art mechanisms being objectionable in one or more major respects. It is, accordingly, a principal aim of the present invention to obviate the shortcomings of the prior art structures and to provide an improved, highly efficient and optically exact endoscopic viewing system which is practical in construction and which provides enhanced overall operability and utility.
It is an important feature of the invention that there is provided a unique optical system for an endoscope ensuring that a greater percentage of the image light rays reach the eyepiece for observation purposes.
Another important feature of the invention is that there is provided a viewing system which permits a full 360.degree. about the optic viewing axis but retains the image in an upright disposition.
Still another important advantage of the novel optical system utilized in the endoscope of the invention is that it obviates any need to twist or otherwise to distort a fiber optical band or bundle.
A basic object of the invention is to provide binocular vision and stereoscopic viewing so that objects located in the field of view may be seen with both eyes to produce a visual image in three dimensions, thereby facilitating more accurate inspection of the field and object viewed.
The improved endoscope of the invention includes, in addition to a highly effective and reliable optical system, the more conventional auxiliary elements such as a surgical element and fluid flow passages. Additional useful elements which may conveniently be incorporated in the preferred embodiment of the invention include fluid pressure sensing and indicator means together with pressure regulator means and gauge means for monitoring and controlling the fluid flow rate and for adjusting and limiting the fluid pressure in the system.
In a preferred embodiment of the invention the optical system includes a dove prism for maintaining an erect or upright viewed image irrespective of rotation of the optical axis of the endoscopic optical system.
The improved endoscope of the invention constitutes an otpical viewing instrument which is more effective for exploring and inspecting interior and inaccessible cavities, such as the various body cavities, and may be used as a diagnostic and surgical instrument.